State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, China.
State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, China; Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station (Ministry of Education & Shanghai Science and Technology Committee), Shanghai, China.
Sci Total Environ. 2021 Jun 15;773:145684. doi: 10.1016/j.scitotenv.2021.145684. Epub 2021 Feb 6.
Intertidal creeks play an important role in transporting nutrients between coastal ecosystems and ocean. Reclamation is a predominant anthropogenic disturbance in coastal regions; however, the influence of reclamation on carbon and nitrogen species and greenhouse gas (GHG) fluxes in creek remains unclear. In a subtropical salt marsh of eastern China, the seasonal patterns of dissolved carbon (DOC, DIC, CO, and CH) and inorganic nitrogen (NH-N, NO-N, and NO-N and NO) species, and the diffusive fluxes of CO, CH, and NO, were compared between the natural tidal creeks and the reclaimed creeks. Due to notably changed hydrological and biological conditions in the reclaimed creeks, concentrations of all dissolved carbon species, NH-N and NO-N increased significantly by 60.2-288.2%, while NO-N and NO decreased slightly, compared to the natural tidal creeks. DIC and NO-N were the primary components of the total dissolved carbon and inorganic nitrogen in both creek types; however, their proportions decreased as a result of elevated DOC, CO, CH, NH-N, and NO-N following reclamation. Significantly higher global warming potential (0.58 ± 0.15 g CO-eq m d) was found in the reclaimed creeks, making them hotspot of greenhouse effects, compared to the natural tidal creeks. Our results indicated that changes in flow velocity, salinity, Chlorophyll a, and pH were the main factors controlling the dissolved carbon and nitrogen and consequent GHG emissions, due to reclamation. This study is helpful in understanding of carbon and nitrogen sink-source shifts resulting from land use changes in coastal wetlands.
潮间带小溪在沿海生态系统和海洋之间的养分输送中发挥着重要作用。填海造地是沿海地区主要的人为干扰活动；然而，填海对小溪中碳和氮物种以及温室气体（GHG）通量的影响尚不清楚。在中国东部的一个亚热带盐沼中，比较了天然潮汐小溪和填海小溪之间溶解碳（DOC、DIC、CO 和 CH）和无机氮（NH-N、NO-N 和 NO-N 和 NO）物种的季节变化以及 CO、CH 和 NO 的扩散通量。由于填海小溪的水文学和生物学条件发生了显著变化，与天然潮汐小溪相比，所有溶解碳物种、NH-N 和 NO-N 的浓度分别显著增加了 60.2-288.2%，而 NO-N 和 NO 略有下降。DIC 和 NO-N 是两种小溪类型中总溶解碳和无机氮的主要成分；然而，由于 DOC、CO、CH、NH-N 和 NO-N 升高，它们的比例在填海后下降。与天然潮汐小溪相比，填海小溪的全球变暖潜势（0.58±0.15 g CO-eq m d）明显更高，使其成为温室效应的热点。我们的研究结果表明，流速、盐度、叶绿素 a 和 pH 的变化是控制溶解碳和氮以及随后温室气体排放的主要因素，这是由于填海造成的。这项研究有助于了解沿海湿地土地利用变化导致的碳氮源汇变化。
